Carl Zeiss SMT GmbHv.Nikon Corporation

Patent Trial and Appeal Board

Nov 5, 2014

11266288 (P.T.A.B. Nov. 5, 2014)

Trials@uspto.gov Paper 41
571-272-7822 Entered: November 4, 2014

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

CARL ZEISS SMT GMBH,
Petitioner,

v.

NIKON CORPORATION,
Patent Owner.

Case IPR2013-00362
Patent 7,348,575 B2

Before HOWARD B. BLANKENSHIP, SALLY C. MEDLEY, and
MATTHEW R. CLEMENTS, Administrative Patent Judges.

CLEMENTS, Administrative Patent Judge.

FINAL WRITTEN DECISION
35 U.S.C. § 318(a) and 37 C.F.R. § 42.73

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I. INTRODUCTION
Carl Zeiss SMT GmbH (“Carl Zeiss”) filed a Petition requesting inter
partes review of claims 1–3, 8–12, 16–20, 23–26, and 29–33 of U.S. Patent
No. 7,348,575 B2 (Ex. 1001, “the ’575 patent”). Paper 3 (“Pet.”). The
Patent Owner, Nikon Corporation (“Nikon”), did not file a Preliminary
Response. On December 16, 2013, we granted an inter partes review for all
challenged claims on certain grounds of unpatentability. Paper 10 (“Dec. to
Inst.”).
After institution of trial, Nikon filed a Patent Owner Response (Paper
19, “PO Resp.”) to which Carl Zeiss filed a Reply (Paper 22, “Reply”).
Additionally, Nikon filed a Motion to Exclude Evidence (Paper 32), to
which Carl Zeiss responded (Paper 36). Nikon then filed a Reply in Support
of its Motion to Exclude. Paper 39.
Carl Zeiss also filed a Motion to Exclude Evidence (Paper 33), to
which Nikon responded (Paper 37). Carl Zeiss then filed a Reply in Support
of its Motion to Exclude. Paper 38.
Oral hearing was held on July 17, 2014.
1

The Board has jurisdiction under 35 U.S.C. § 6(c). This Final Written
Decision is issued pursuant to 35 U.S.C. § 318(a) and 37 C.F.R. § 42.73.
Carl Zeiss has shown by a preponderance of the evidence that claims
1–3, 8–12, 16–20, 23–26, and 29–33 of the ’575 patent are unpatentable.

1
A transcript of the oral hearing is included in the record as Paper 40
(“Tr.”).
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A. The ’575 Patent
The subject matter of the ’575 patent relates to a catadioptric
projection optical system, exposure apparatus, and exposure method and,
more particularly, to a high-resolution catadioptric projection optical system
suitable for use in production of semiconductor devices and liquid-crystal
display devices by photolithography. Ex. 1001, 1:18–23. In the production
of semiconductor devices, photolithography uses a projection exposure
apparatus to project an “image of a mask (or a reticle) through a projection
optical system onto a wafer (or a glass plate or the like) coated with a
photoresist or the like.” Id. at 1:27–32. As the dimensions of semiconductor
devices shrink, the projection optical system of the projection exposure
apparatus requires greater resolving power (resolution). Id. at 1:32–36. In
order to satisfy the requirements for the resolving power of the projection
optical system, it is necessary to shorten the wavelength of illumination light
(exposure light) and to increase the image-side numerical aperture of the
projection optical system. Id. at 1:37–41. It was known to increase the
numerical aperture by putting a medium with a high refractive index, like a
liquid, in the optical path between the projection optical system and the
image plane. Id. at 1:55–58. However, there were known disadvantages to
this approach. Id. at 1:59–67.
The ’575 patent discloses systems and methods to provide a relatively
compact projection optical system that is “corrected for various aberrations,
such as chromatic aberration and curvature of field, and being capable of
securing a large effective image-side numerical aperture while well
suppressing the reflection loss on optical surfaces.” Id. at 2:3–9. A medium
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having a refractive index larger than 1.1, such as deionized water, is
interposed in the optical path between the boundary lens and the image
plane, thereby increasing the image-side numerical aperture. Id. at 5:9–21.
The projection optical system is catadioptric, comprising at least two
reflecting mirrors, in which every transmitting member and every reflecting
member with a refracting power are arranged along a single optical axis and
in which the projection optical system has an effective imaging area that
does not include the optical axis. Id. at 5:39–45. By arranging the
transmitting members and the reflecting members along a single axis, the
system is easier to produce than a system wherein the optical members are
arranged along multiple optical axes. Id. at 5:52–59.
B. Illustrative Claim
Claim 1 is illustrative and is reproduced below:
1. A catadiopt[ri]c projection optical system, which forms a
reduced image of a first surface on a second surface,
comprising:
at least two reflecting mirrors; and
a boundary lens whose surface on the first surface side
has a positive refractive power,
wherein where a refractive index of an atmosphere in an
optical path of the projection optical system is 1, an optical path
between the boundary lens and the second surface is filled with
a medium having a refractive index la[r]ger than 1.1,
wherein every transmitting member and every reflecting
member with a refractive power constituting the projection
optical system are arranged along a single optical axis; and
the projection optical system having an effective imaging
area of a predetermined shape not including said optical axis.
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C. Prior Art Supporting the Instituted Challenges
Carl Zeiss relies on the following prior art references, as well as the
Declaration of Richard C. Juergens (Ex. 1016):
Terasawa US 2002/0024741 A1 Feb. 28, 2002 Ex. 1008
Suwa US 5,825,043 Oct. 20, 1998 Ex. 1009
Switkes M. Switkes & M. Rothschild,
Resolution Enhancement of
157 nm Lithography by
Liquid Immersion, 4691
PROC. SPIE 459–465 (2002)
2002 Ex. 1010
Ulrich Willi Ulrich et al., The
Development of Dioptric
Projection Lenses for DUV
Lithography, 4832 PROC.
SPIE 158–169 (2002)
2002 Ex. 1011
Fukami
2
WO 99/49504 Sept. 30,
1999
Ex. 1012
Asai Satoru Asai et al., Resolution
Limit for Optical Lithography
Using Polarized Light
Illumination, 32 JAPAN J.
APPL. PHYS. 5863–5866
(1993)
Dec. 1993 Ex. 1013
Carl Zeiss refers to Suwa, Switkes, Ulrich, and Fukami collectively as
the “Immersion References.” Pet. 4.

2
Fukami is a Japanese language document. Ex. 1012. Unless indicated
otherwise, all subsequent references to Fukami in this decision will refer to
its certified English language translation. Ex. 1015.
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D. The Instituted Challenges of Unpatentability
We instituted trial based on the following grounds of unpatentability:
References Basis Claim[s] challenged
Terasawa and the
Immersion References
§ 103 1–3, 8–12, 16–20, 23–26, 29, and
31–33
Terasawa, the Immersion
References, and Asai
§ 103 30
II. ANALYSIS
A. Claim Construction
In an inter partes review, claim terms in an unexpired patent are
interpreted according to their broadest reasonable construction in light of the
specification of the patent in which they appear. 37 C.F.R. § 42.100(b);
Office Patent Trial Practice Guide, 77 Fed. Reg. 48,756, 48,766 (Aug. 14,
2012). Also, claim terms are given their ordinary and customary meaning,
as would be understood by one of ordinary skill in the art in the context of
the entire disclosure. In re Translogic Tech., Inc., 504 F.3d 1249, 1257
(Fed. Cir. 2007).
Carl Zeiss contends that the words in the challenged claims generally
should have their plain meaning. Pet. 13. However, Carl Zeiss provides its
own interpretations of five terms—“boundary lens,” “a refractive index . . .
is 1,” “effective imaging area,” “every effective imaging area,” and “the
second imaging optical system.” Pet. 13–15. Nikon provides an
interpretation only for “boundary lens.” PO Resp. 16–19. For this decision,
we construe each of these claim terms in turn.
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1. “boundary lens” (claim 1)
Claim 1 requires a “boundary lens.” Carl Zeiss contends that “when
an immersion liquid is introduced between the last lens element of the
projection optical system and the wafer (as in limitation [1d]), the last lens
element becomes a ‘boundary lens.’” Pet. 14. This is consistent with the
use of the term “boundary lens” in the ’575 patent. See, e.g., Ex. 1001,
20:45–49 (“FIG. 3 is an illustration schematically showing a configuration
between the boundary lens and the wafer in the first example of the present
embodiment.”) (emphasis removed), Figs. 3, 4, 5, 7 (each depicting
boundary lens Lb as the last lens element). Accordingly, in the Decision to
Institute, we construed “boundary lens” as “the last lens element of the
projection optical system.” Dec. to Inst. 8.
Nikon contends that a “boundary lens” is not merely any lens that is
placed in contact with an immersion liquid, but rather “a lens of the
projection optical system that has a convex object-side surface and a flat
image-side surface to increase effective NA in the presence of the immersion
liquid by reducing reflection loss.” PO Resp. 16 (citing Ex. 1001, 5:22–31,
Tables 1–11; Ex. 2024 ¶ 66). Nikon points to Figure 3 as depicting a
boundary lens, and argues that a person of ordinary skill in the art would
have understood that “a boundary lens needed to be designed to not only
isolate an atmosphere of the projection optical system, but also stand a
higher fluence from the light source and enable higher resolution by
reducing reflection losses.” Id. at 17–18.
Carl Zeiss counters that nothing in the portions of the ’575 patent
cited by Nikon constitutes lexicography or disavowal of the plain and
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ordinary meaning of “boundary lens.” Reply 1–3. Claim 1 does not require
that the image-side surface be “flat,” and the passage at column 5, lines 22 to
31, merely describes what is “feasible” and “can be” secured. Id. Carl Zeiss
also argues that Nikon’s proposed construction does not make technical
sense because, as even Nikon’s expert conceded, it is the whole system, not
just the boundary lens, that increases effective NA when an immersion
liquid is used between the boundary lens and the image plane. Id.
We are not persuaded that “boundary lens” should be construed to
require “a convex object-side surface.” Claim 1 already requires that the
“surface on the first surface side [of the boundary lens] has a positive
refracting power.” To construe the term “boundary lens” to include this
limitation would render this language of the claim limitation superfluous.
We also are not persuaded that “boundary lens” should be construed
to require “a flat image-side surface.” Although Figure 3 depicts boundary
lens Lb with a flat image side, Figure 3 does not amount to a definition of
“boundary lens.” With respect to Figure 3, the ’575 patent states that, “the
boundary lens Lb in the first example has a convex surface kept toward the
reticle (first surface). In other words, the reticle-side surface Sb of the
boundary lens Lb has a positive refracting power.” Ex. 1001, 20:48–51.
The description of Figure 3 is silent, however, with respect to whether the
image-side surface must be flat. Id. at 20:45–54. Moreover, Nikon’s
reliance on column 5, lines 22 to 31, is unavailing because it describes only
a “first aspect of the embodiment.” And in describing that aspect, as in
describing Figure 3, the ’575 is silent with respect to whether the image-side
surface must be flat. It says only that, “the optical surface on the object side
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(first surface side) of the boundary lens is provided with the positive
refracting power, whereby the reflection loss is reduced on this optical
surface and, in turn, the large effective image-side numerical aperture can be
secured.” Id. at 5:23–27. Thus, whereas Nikon’s proposed construction
would require a convex object-side surface and a flat image-side surface,
this passage of the ’575 patent suggests that a boundary lens needs only a
positive refracting power—i.e., convex object-side surface—to reduce
reflection loss and, in turn, increase effective NA in the presence of an
immersion liquid.
Finally we are not persuaded that “boundary lens” should be
construed to include a purpose—i.e., “to increase effective NA in the
presence of the immersion liquid by reducing reflection loss.” Although this
purpose is referenced in column 5 of the ’575 patent, we decline to import a
description of a “first aspect of the embodiment” into the construction of a
claim term.
Accordingly, we maintain our construction of “boundary lens” as “the
last lens element of the projection optical system.”
2. “a refractive index . . . is 1” (claim 1)
Carl Zeiss contends that “a refractive index . . . is 1” should be
interpreted as “equal to 1 to within at least the first decimal place.” Pet. 14.
Carl Zeiss’s proposal is consistent with the ’575 patent’s use of the first
decimal place later in claim 1 (“having a refractive index la[r]ger than 1.1”).
Specifically, the use of the first decimal place—i.e., “1.1”—elsewhere in the
claim implies that the recited “1” means “1.0;” otherwise the first decimal
place—i.e., the first digit to the right of the decimal—would have been
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specified there as well. Carl Zeiss’s proposal is also consistent with the
examples in the Specification of the atmosphere in the projection optical
system being an inert gas, such as helium or nitrogen, which has a refractive
index close to, but not exactly, equal to 1. Ex. 1001, 20:24–44; see also
Ex. 1016 ¶¶ 86–92. Accordingly, we construe “a refractive index . . . is 1”
as “a refractive index . . . equal to 1 within at least the first decimal place.”
3. “effective imaging area” (claim 1)
Carl Zeiss contends that “effective imaging area” should be
interpreted to mean the same thing as “effective exposure area” and
“effective exposure region ER.” Pet. 15. The ’575 patent states that “FIG. 2
is an illustration showing a positional relation between the optical axis and
an effective exposure area of arcuate shape,” and that “an effective exposure
region (effective imaging area) ER is set in an arcuate shape.” Ex. 1001,
19:65–20:9 (emphasis removed). Based on our review of the Specification,
we agree that these terms are used interchangeably.
4. “every effective imaging area” (claim 18)
Carl Zeiss contends that “every effective imaging area” should be
interpreted to mean “the effective imaging area formed on the second
surface as the final image, as well as effective imaging areas corresponding
to any intermediate images.” Pet. 15. The term “every effective imaging
area” is not used in the ’575 patent outside of claim 18. As support for its
position, Carl Zeiss cites only to the Declaration of Richard C. Juergens. Id.
(citing Ex. 1016 ¶ 93). The ’575 patent describes an “effective imaging
area” and describes “intermediate images,” but does not describe “effective
imaging areas corresponding to any intermediate images.” Specifically, the
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“effective imaging area” is the arcuate shape formed on a wafer, as depicted
in Figure 2, reproduced below.

Ex. 1001, Fig. 2, 19:65–20:23. Figure 2 depicts the “effective imaging area”
as an arcuate shape formed on a wafer. In contrast, “intermediate images”
are images of the reticle formed on various components of the first imaging
optical system and second imaging optical system. See, e.g., Ex. 1001,
21:56–67. Because the ’575 patent refers only to an area on a wafer as the
“effective imaging area,” and never once refers to an intermediate image as
having a corresponding effective imaging area, Carl Zeiss has not presented
sufficient and credible evidence that patentee intended “every effective
imaging area” to encompass “effective imaging areas corresponding to any
intermediate images.” Based on our review of the Specification, “every
effective imaging area” refers to all of the effective imaging areas of the
claimed projection optical system, of which there is only one: the “effective
imaging area” recited in claim 1. Accordingly, we construe “every effective
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imaging area” as commensurate in scope with the “effective imaging area”
recited in claim 1.
5. “the second imaging optical system” (claim 25)
Carl Zeiss contends that “the second imaging optical system” should
be interpreted to mean the “second lens unit” recited in claim 10. Pet. 15–
16. We disagree. Claim 25 recites “wherein the second imaging optical
system is a dioptric system consisting of only a plurality of transmitting
members.” Claim 25 depends from claims 1 and 10. However, neither
claim 1 nor claim 10 recites a “second imaging optical system.” The
Specification is ambiguous. The ’575 patent does not describe only a
“second imaging optical system” or only a “second lens unit” as “consisting
of only a plurality of transmitting members.” All described embodiments of
the “second lens unit” described in the ’575 patent “consist[] only of a
plurality of transmitting members.” Ex. 1001, Figs. 5, 7, 9, 14, 15, 16.
Some, but not all, embodiments of the “second imaging optical unit” are
“dioptric systems consisting of only of a plurality of transmitting members.”
See, e.g., Ex. 1001, Fig. 5 (second imaging optical system G2 consisting
only of lenses), Fig. 7 (second imaging optical system G2 consisting only of
lenses), Fig. 14 (second imaging optical system G2 consisting only of
lenses), Fig. 15 (second imaging optical system G4 consisting only of
lenses), Fig. 16 (second imaging optical system G6 consisting only of
lenses). At least one embodiment of the “second imaging optical system” is
not. Ex. 1001, Fig. 9 (second imaging optical system G2 including two
reflecting mirrors M3 and M4).
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Claims 20, 21, 22, 23, 24, and 26 all depend, directly or indirectly,
from claim 19. Claim 19 recites a “first imaging optical system” and a
“second imaging optical system.” Claim 20 depends from claim 19 and
defines further limitations on the “first imaging optical system” recited in
claim 19. In this context, claim 25’s recitation of “[t]he projection optical
system according to claim 10” (emphasis removed) appears to be a
typographical error in which “10” should be “19” or “20.” Accordingly, we
construe “the second imaging optical system” to mean the “second imaging
optical system” recited in claim 19.
B. Whether Mr. Juergens is an Expert
Nikon contends that, “[b]ecause of the highly specialized nature of
projection optical systems,” the level of ordinary skill in the art would have
required at least two years of experience in the lithography optics industry
and experience in the specification of projection optical systems. PO Resp.
15–16. Nikon further contends that Mr. Juergens is not an expert in the
relevant field because he does not have the experience required to be a
person of even ordinary skill in the art.
3
Id. at 35–38.
Carl Zeiss counters that Nikon’s expert, Dr. Jose Sasian, invites Mr.
Juergens to guest lecture Dr. Sasian’s class on lens design, and that Dr.
Sasian conceded that Mr. Juergens is an expert on many aspects of optical
design. Reply 13, n.2.

3
Nikon also asserts that exclusion of Mr. Juergens’ testimony would be
justified. PO Resp. 38. Nikon does not, however, move to exclude either
the Declaration of Mr. Juergens submitted with the Petition (Ex. 1016) or the
Declaration of Mr. Juergens submitted with the Reply (Ex. 1036). Paper 32.
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Having considered the parties’ arguments and evidence, we are not
persuaded that the level of ordinary skill in the art required at least two years
of experience in the lithography optics industry and experience in the
specification of projection optical systems. The claims are not limited to the
field of lithography. Rather, based on the art of record, we find that the
relevant field is projection optical systems. Mr. Juergens holds an M.A. in
Physics and has more than 40 years of experience in the field of optical
system design, including catoptric, dioptric, and catadioptric systems. Ex.
1016 ¶¶ 3–9. Accordingly, we are persuaded that Mr. Juergens is a person
of at least ordinary skill in the art in the art of projection optical systems.
C. Claims 1–3, 8–12, 16–20, 23–26, 29, and 31–33 –
Obvious over Terasawa and the Immersion References
Carl Zeiss alleges that claims 1–3, 8–12, 16–20, 23–26, 29, and 31–33
are unpatentable under 35 U.S.C. § 103(a) over Terasawa and the Immersion
References. Pet. 31–50, 55–56. Carl Zeiss cites Terasawa as teaching every
limitation, but acknowledges that Terasawa does not disclose expressly “an
optical path between the boundary lens and the second surface is filled with
a medium having a refractive index larger than 1.1,” as recited in claim 1.
Id. at 34, 55. For that limitation, Carl Zeiss cites to the Immersion
References (Suwa, Switkes, Ulrich, and Fukami). Id. at 36, 44–50, 55–56.
Nikon counters that (1) Terasawa and the Immersion References do
not teach, suggest, or otherwise render obvious a “boundary lens,” as
properly construed; (2) a person of ordinary skill in the art would not have
had a reasonable expectation of success in combining the references; and
(3) secondary considerations demonstrate nonobviousness. PO Resp. 38–47.
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Upon consideration of the parties’ contentions and supporting
evidence, we determine that Carl Zeiss has demonstrated by a preponderance
of the evidence that claims 1–3, 8–12, 16–20, 23–26, 29, and 31–33 are
unpatentable as obvious over Terasawa and the Immersion References. Pet.
31–50, 55–56. In our discussion below, we address Nikon’s arguments
presented in the Patent Owner Response.
Terasawa (Ex. 1008)
Terasawa describes a projection optical system and a projection
exposure apparatus for projecting a pattern of a mask onto a substrate
through the projection optical system. Ex. 1008 ¶ 1. Figure 1 of Terasawa,
reproduced below, depicts a catadioptric projection optical system including
a first imaging system G1 and a second imaging system G2 for projecting an
image of reticle 101 illuminated with illumination system (not shown) onto
wafer 102:

Figure 1 of Terasawa depicts a catadioptric projection optical system. Id.
¶¶ 55, 102, 103. “The first imaging optical system G1 comprises, in order
from the object side, at least a first mirror M1, having a refracting element
L1, [and] a second mirror M2.” Id. ¶ 103. Light from reticle 101 is imaged
by first imaging optical system G1, whereby intermediate image Io is
formed. Id. Intermediate image Io, as imaged by first imaging optical
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system G1, is then imaged on wafer 102 by second imaging optical system
G2, comprising a refracting element, at a predetermined magnification. Id.
In the structure described above, the optical system of the first embodiment
has one optical axis 103, and produces a multiple-number imaging optical
system wherein abaxial light, without light interception of a pupil, is imaged.
Id. With the structure described above, light can be directed to the second
imaging optical system without a void in a pupil and without bend of the
optical axis. Id. ¶ 105. The region of the object plane from which the light
reaches the image plane, and which is attributable to the imaging, is a semi-
arcuate zone. Id. at Fig. 3, ¶ 117.
Suwa (Ex. 1009)
Suwa describes “a means for improving the resolution without largely
increasing the numerical aperture of the projection optical system,” in which
“an immersion projection method may be used in which the space between
the wafer and the projection optical system is filled with a liquid.” Ex. 1009,
3:18–23. Specifically:
In this immersion projection method, the air space
between the wafer and the optical element constituting the
projection optical system on the projection end side (image
plane side) is filled with a liquid having a refractive index close
to the refractive index of the photoresist layer, to increase the
effective numerical aperture of the projection optical system
seen from the wafer side, i.e. improving the resolution. This
immersion projection method is expected to attain good
imaging performance by selecting the liquid used.
Id. at 3:24–33. Figure 9 of Suwa is reproduced below:
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Figure 9 of Suwa depicts a projection optical system (PL) with an immersion
fluid (LQ). Id. at 23:59-65. Suwa discloses that the last lens element, LE1,
is a “positive lens element [] having a flat lower surface Pe and a convex
upper surface,” and “is fixed on the end of the projection lens system PL
inside the lens barrel.” Id. at 23:9–11. Suwa also discloses that the
projection optical system can be catadioptric. Id. at 20:13–21. Carl Zeiss
acknowledges that Suwa does not disclose expressly that the liquid has a
refractive index greater than 1.1, but contends that:
[A person of ordinary skill in the art] would know that “a
refractive index close to the refractive index of the photoresist”
would be a refractive index greater than 1.1. For example, U.S.
Patent No. 4,346,164 (“Tabarelli”), to which the passage from
Suwa cited above expressly refers, identifies the refractive
index of the photoresist as 1.6, and goes on to list nine
immersion liquids with refractive indices between 1.5 and 1.66.
(ZEISS 1016; ¶¶ 199-201; ZEISS 1025, 3:57-60, 5:36-50.)
Pet. 45. We are persuaded by Carl Zeiss’s reasoning.
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Switkes (Ex. 1010)
Switkes teaches that immersion lithography can be used to enhance
resolution by increasing numerical aperture and also can be used to increase
depth of focus. Ex. 1010, 459 (“Immersion lithography is a technique which
can enhance the resolution of projection lithography by permitting exposures
with numerical aperture (NA) greater than one, the theoretical maximum for
conventional ‘dry’ systems. . . . Liquid immersion also increases the wafer
depth of focus, i.e. the tolerable error in the vertical position of the wafer, by
the index of the immersion liquid compared to a dry system with the same
numerical aperture.”) (footnotes omitted). Switkes describes several
immersion liquids for use at 157 nm and 193 nm whose refractive indexes
are greater than 1.2. Id. at 461. Switkes describes how immersion can be
used with “much of conventional designs.” Id.
Ulrich (Ex. 1011)
Ulrich describes the application of immersion lithography to prior art
“dry” designs to achieve increased numerical aperture. Ex. 1011, 166–167.
Ulrich expressly teaches that “immersion designs can be applied to other
design concepts such as catadioptric designs with similar results.” Id. at
167.
Fukami (Ex. 1015)
Fukami describes the use of liquid immersion to improve the
resolution of conventional projection exposure apparatuses. Ex. 1015, 3:13–
28.
4
Fukami expressly describes the applicability of immersion techniques

4
Page numbers refer to the bottom number on the page.
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to a catadioptric optical projection system having two mirrors and a single
optical axis. Id. at 21:13–16 (“Furthermore, the projection optical system
PL can be a dioptric, catoptric, or catadioptric system, for example an optical
system which has a plurality of dioptric elements and two catoptric elements
(at least one of which is a concave mirror) disposed on an optical axis
extending straight without being bent . . . .”).
Boundary lens
Nikon contends that Terasawa’s last lens immediately prior to wafer
102 is not a “boundary lens” as construed by Nikon because it does not
increase numerical aperture by reducing reflection loss. PO Resp. 38–39.
We decline to adopt Nikon’s proposed construction of “boundary lens” for
the reasons discussed above. Based on our construction of boundary lens,
Terasawa’s last lens immediately prior to wafer 102 is a “boundary lens”
because it is the last lens element of the projection optical system. Pet. 36.
Reason to combine and reasonable expectation of success
Carl Zeiss contends that “Ulrich demonstrates that the level of
ordinary skill in this art is high and how, at the time of the alleged invention,
there was not only express teaching to modify prior art ‘dry’ catadioptric
projection optical system to include the immersion limitation to thereby
increase NA, but also the skill necessary to do so.” Pet. 48 (citing Ex. 1016
¶¶ 22–24, 77–81, 223–224).
Nikon contends that a person of ordinary skill in the art would not
have had a reasonable expectation of success in combining the references
because introducing an immersion liquid into a dry projection optical system
such as Terasawa’s would create technical problems that would render it
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inoperative. Id. at 39 (citing Ex. 2024 ¶¶ 119, 120). Specifically, Nikon
argues that neither increasing NA nor increasing DOF would have led a
person of ordinary skill in the art to combine the references because
(1) adding an immersion liquid to Terasawa would cause technical problems
that would have required undue experimentation and design to solve; and
(2) a person of ordinary skill in the art would not have increased DOF at the
expense of NA. Id. at 40–43. Carl Zeiss counters that nothing in claim 1 or
the ’575 patent addresses the problems identified by Nikon, and that Nikon’s
expert, Dr. Sasian, conceded that a person of ordinary skill in the art could
have addressed those challenges at the time of the invention. Reply 6–7
(citing Ex. 1033).
Having reviewed the parties’ contentions and evidence, we are
persuaded that a person of ordinary skill in the art would have had a
reasonable expectation of success in combining the references. Nikon’s
argument assumes that a person of ordinary skill in the art would introduce
an immersion liquid into the dry projection optical system of Terasawa
without any further modification. In the Petition, however, Carl Zeiss
argued that “Ulrich also demonstrates that a POSITA at the time of the
alleged invention would have been able to modify the systems . . . to include
the immersion liquid to increase NA.” Pet. 52 (emphasis added). Ulrich
teaches, for example, that “the high-NA dry projection lenses were not taken
as a straight forward starting point but well-known and proven know-how of
design history was fallen back on,” and that routine optimizations (“scaling
of the two partial focus widths,” “splitting thick lenses,” and “adding
aspheres”) can be used to achieve the level of performance desired for
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projection microlithography. Ex. 1011, 166; Reply 10 (citing Ex. 1016
¶¶ 220, 221). Thus, Nikon’s assumption is improper. In any event, the
technical problems identified by Dr. Sasian relate to the need to characterize
the optical properties of an immersion fluid, and Dr. Sasian concedes that
the experiments necessary to do so were “comparable” to the techniques
known and used to characterize materials such as silica glass. See, e.g.,
Ex. 1033, 80:13–87:13. Accordingly, we are persuaded that a person of
ordinary skill in the art at the time would have had a reasonable expectation
of success in combining Terasawa and the Immersion References.
Secondary considerations
Factual inquiries for an obviousness determination include secondary
considerations based on evaluation and crediting of objective evidence of
nonobviousness. Graham v. John Deere Co. of Kansas City, 383 U.S. 1, 17
(1966). Notwithstanding what the teachings of the prior art would have
suggested to one with ordinary skill in the art at the time of the ’575 patent’s
invention, the totality of the evidence submitted, including objective
evidence of nonobviousness, may lead to a conclusion that the challenged
claims would not have been obvious to one with ordinary skill in the art. In
re Piasecki, 745 F.2d 1468, 1471–72 (Fed. Cir. 1984). Secondary
considerations may include any of the following: long-felt but unsolved
needs, failure of others, unexpected results, commercial success, copying,
licensing, and praise. See Graham, 383 U.S. at 17; Leapfrog Enters., Inc. v.
Fisher-Price, Inc., 485 F.3d 1157, 1162 (Fed. Cir. 2007).
To be relevant, evidence of nonobviousness must be commensurate in
scope with the claimed invention. In re Kao, 639 F.3d 1057, 1068 (Fed. Cir.
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2011) (citing In re Tiffin, 448 F.2d 791, 792 (CCPA 1971)); In re Hiniker
Co., 150 F.3d 1362, 1369 (Fed. Cir. 1998). In that regard, in order to be
accorded substantial weight, there must be a nexus between the merits of the
claimed invention and the evidence of secondary considerations. In re
GPAC Inc., 57 F.3d 1573, 1580 (Fed. Cir. 1995). “Nexus” is a legally and
factually sufficient connection between the objective evidence and the
claimed invention, such that the objective evidence should be considered in
determining nonobviousness. Demaco Corp. v. F. Von Langsdorff Licensing
Ltd., 851 F.2d 1387, 1392 (Fed. Cir. 1988). The burden of showing that
there is a nexus lies with the patent owner. Id.; see In re Paulsen, 30 F.3d
1475, 1482 (Fed. Cir. 1994).
Nikon alleges that there was a long-felt need in the semiconductor
industry for higher resolution, and that the ’575 patent met that need. PO
Resp. 43–45. Specifically, Nikon cites Figure 53 of the 2003 Edition of the
International Technology Roadmap for Semiconductors, and asserts that
“there is no evidence of record that the industry need for [the 65 nm and 45
nm technology nodes] had been met prior to the invention in the 575
Patent.” Id. at 44. Nikon, however, bears the burden of establishing that the
long-felt need for higher resolution was unmet. Figure 53 indicates that
development was underway for the 65 nm and 45 nm technology nodes, but
does not provide any indication of the state of immersion lithography.
Accordingly, Nikon has not provided persuasive evidence that the alleged
need was long-felt and unmet prior to the invention of the ’575 patent.
Nikon also alleges that the initial skepticism toward immersed
catadioptric systems is evidence of the nonobviousness of claim 1. Id. at
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45–46. Nikon’s argument is predicated on the “surprise” expressed in a
paper authored by employees of Carl Zeiss. Id. at 46 (citing Ex. 2005, 3:9,
3:12, 5:28). Carl Zeiss counters that the “surprise” expressed in the article
relates to a folded design that Nikon’s expert, Dr. Sasian, concedes is outside
the scope of claim 1, and to the introduction of intermediate images without
increasing the volume and weight of the lens, which Dr. Sasian concedes is
not a limitation of claim 1. Reply 11 (citing Ex. 2005, 3, 5). Having
reviewed the parties’ contentions and evidence, we are not persuaded that
the “surprise” expressed in the paper is evidence of initial skepticism
towards the immersed catadioptric projection optical system recited in
claim 1.
Finally, Nikon alleges acceptance and copying on the grounds that a
2003 paper by Nikon employees is cited in a 2005 paper by Carl Zeiss
employees. PO Resp. 46 (citing Ex. 2005, 8:19–20). None of the evidence
submitted by Nikon, however, demonstrates that a Carl Zeiss product falls
within the scope of any claim of the ’575 patent, that Carl Zeiss was aware
of the ’575 patent prior to developing its product, or that Carl Zeiss
developed its product by copying the ’575 patent.
After weighing all of the evidence of obviousness and nonobviousness
of record, on balance, we conclude that the strong evidence of obviousness
outweighs the weak evidence of non-obviousness.
Whether Terasawa and the Immersion References are enabling
Nikon contends that the combination of Terasawa and the Immersion
References fails to enable a person of ordinary skill in the art to make and
use the subject matter of claim 1 of the ’575 patent. PO Resp. 25–35.
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Specifically, Nikon argues that the proposed combination does not enable
claim 1 because (1) a significant quantity of experimentation was necessary,
as evidenced by the lapse of more than one year from the publication of
Ulrich to the filing of Carl Zeiss’s first provisional application directed to a
catadioptric immersion system; (2) the Immersion References do not provide
adequate direction or guidance because none of them contain prescription
tables for an immersed catadioptric projection optical system; (3) the nature
of the invention is such that in 2003 the industry projected that development
of an immersion lithography system would take two more years; (4) a person
with at least two years of experience in lithography optics and projection
optical systems would not have been able to make and use the claimed
invention because even a much more experienced person—Mr. Wilhelm
Ulrich of Carl Zeiss—had not done so before the subject matter of the ’575
patent was invented; and (5) projection optical systems present unpredictable
design problems, such as beam separation, field height, and color correction,
as evidenced by the 2005 paper authored by employees of Carl Zeiss. Id.
Carl Zeiss counters that the prior art need enable only a single
embodiment within the scope of claim 1, not the full scope of the claim, and
that Nikon and Dr. Sasian’s arguments about the alleged shortcomings are
not commensurate with the limitations recited in claim 1. Reply 5–6.
We have reviewed Nikon’s argument and supporting evidence, as well
as the responsive argument and supporting evidence of Carl Zeiss, and are
unpersuaded that the combined teachings of Terasawa and the Immersion
References would not have enabled one with ordinary skill in the art to make
a catadioptric projection optical system with a single optical axis in which
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the optical path between the boundary lens and the surface on which the
image is projected is filled with a medium having a refractive index larger
than 1.1 without undue experimentation.
The issue is whether the amount of required experimentation is undue,
not whether any experimentation is necessary. In re Vaeck, 947 F.2d 488,
495 (Fed. Cir. 1991). In re Angstadt, 537 F.2d 498, 504 (CCPA 1976). The
factors suitable for consideration include (1) the quantity of experimentation
necessary, (2) the amount of direction or guidance presented, (3) the
presence or absence of working examples, (4) the nature of the invention,
(5) the state of the prior art, (6) the relative skill of those in the art, (7) the
predictability or unpredictability of the art, and (8) the breadth of the claims.
See In re Wands, 858 F.2d 731, 737 (Fed. Cir. 1988).
With respect to quantity of experimentation, neither Nikon nor
Dr. Sasian explain with sufficient specificity what and how much
experimentation would have been required by one with ordinary skill, and
why that amount of experimentation should be regarded as undue. PO Resp.
31 (citing Exs. 2020; 2024 ¶¶ 106, 107). Nikon argues that more than one
year passed between the publication of Ulrich in 2002 and the filing of Carl
Zeiss’s first provisional application directed to a catadioptric immersion
system. We understand Nikon to be arguing that the amount of
experimentation should be inferred to be undue based on the passage of
more than one year. Even assuming that Carl Zeiss was experimenting
during that time period, however, there is not sufficient evidence that the
amount of experimentation was undue; it may have been only complex. The
fact that experimentation may be complex does not necessarily make it
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undue if those of skill in the art typically engage in such experimentation. In
re Wands, 858 F.2d at 737.
With respect to the amount of direction or guidance, Nikon’s
argument that none of the Immersion References include prescription tables
for a projection optical system is not persuasive. PO Resp. 31. The
Immersion References are not relied upon to teach a catadioptric projection
optical system so those references would not be expected to include a
prescription table for a catadioptric projection optical system. Moreover,
claim 1 does not recite a prescription table and Nikon does not explain
persuasively why a person of ordinary skill in the art could not have
modified a prescription table taught in Terasawa.
With respect to the nature of the invention and the state of the prior
art, Nikon argues that Figure 53 of the 2003 International Technology
Roadmap for Semiconductors (Ex. 2003) indicates that “for the 65 nm node,
the narrowing of options for immersion lithography was not expected until
2004, and the qualification and pre-production states were not expected until
2005.” PO Resp. 32. Figure 53 depicts, however, a narrowing of options for
the 65 nm node generally, not for immersion lithography in particular.
Moreover, the Roadmap takes into account challenges beyond just the
construction of a projection optical system. Many of the “Difficult
Challenges” identified by the Technology Roadmap, for example, relate to
factors other than the projection optical system, such as mask requirements
and resist requirements. Ex. 2003, 4. Accordingly, there is not sufficient
evidence that the narrowing of options and the move to qualification and
pre-production states shown in Figure 53 was driven by the amount of
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experimentation required by a person of ordinary skill in the art to make and
use an immersed catadioptric projection optical system.
With respect to the relative skill of those in the art, the fact that
Mr. Ulrich recognized in 2002 that “parallel work must be performed on
solving the technological challenges” (Ex. 1011, 167) does not establish that
such work required undue experimentation. Even assuming that the
experimentation required to solve the technological challenges referred to
would be complex, it is not necessarily undue if those of skill in the art
typically engage in such experimentation. In re Wands, 858 F.2d at 737.
Finally, with respect to the predictability of the art, the Carl Zeiss
paper does not establish sufficiently that resolution of the problems
identified required undue experimentation. In some cases the paper
describes how each of the design problems was resolved by known
techniques, such as a “concept that has already been studied for lithography”
(Ex. 2005, 2), or “the rule [to] ‘separate the beams directly at intermediate
images’” (id. at 5). Although the authors expressed “surprise” at results with
folded designs, such designs are outside the scope of claim 1. Reply 11.
The only surprise expressed by the authors with respect to inline systems
(like claim 1 of the ’575 patent) is that “the introduction of additional
intermediate images, which enhances the system complexity at the first
glance, does not increase volume or weight of the lens. In some cases, the
results even surpass the ‘simpler’ designs.” Ex. 2005, 5 (emphasis added).
The surprise, therefore, related to the volume and weight of the lens, not to
whether an immersed catadioptric projection optical system could be made.
Moreover, with respect to design challenges identified elsewhere in Nikon’s
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Patent Owner Response, Dr. Sasian conceded that the experiments necessary
to characterize the optical properties of an immersion fluid were
“comparable” to the techniques known and used to characterize materials
such as silica glass. See, e.g., Ex. 1033, 80:13–87:13.
For all of the foregoing reasons, Nikon has not demonstrated
adequately that Terasawa and the Immersion References are non-enabling
prior art.
Conclusion
For the foregoing reasons, we determine that Carl Zeiss has
demonstrated by a preponderance of the evidence that claims 1–3, 8–12, 16–
20, 23–26, 29, and 31–33 are unpatentable under 35 U.S.C. § 103(a) as
obvious over Terasawa and the Immersion References.
D. Claim 30 – Obvious over Terasawa, the Immersion References, and Asai
Carl Zeiss alleges that claim 30 is unpatentable under 35 U.S.C.
§ 103(a) over Terasawa, the Immersion References, and Asai. Pet. 59–60.
Carl Zeiss acknowledges that Terasawa does not disclose expressly
“illumination light which is s-polarized with respect to the second surface,”
as recited in claim 30 (id. at 59), but cites Asai for teaching that feature. Id.
at 59–60.
Nikon counters that claim 30 would not have been obvious over
Terasawa, the Immersion References, and Asai because Asai does not cure
the alleged deficiencies of Terasawa and the Immersion References with
respect to independent claim 1, from which claim 30 depends ultimately.
PO Resp. 47.
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Asai describes the use of S-polarized light in a high-numerical-
aperture optical stepper system. Ex. 1013, Abstract. Specifically, Asai
describes how “[l]ight polarized parallel to the plane of incidence, or P
polarization, gives lower contrast images than light polarized perpendicular
to the plane of incidence, or S polarization, because destructive interference
between diffracted waves does not occur when the electric-field vectors are
perpendicular.” Id at 5863 (footnotes omitted).
Upon consideration of the parties’ contentions and supporting
evidence, we determine that Carl Zeiss has demonstrated by a preponderance
of the evidence that claim 30 is unpatentable as obvious over Terasawa, the
Immersion References, and Asai. Pet. 59–60.
As discussed above, we are not persuaded by Nikon’s arguments that
Terasawa and the Immersion References do not teach the limitations of
independent claim 1, from which claim 30 depends ultimately.
For the foregoing reasons, we determine that Carl Zeiss has
demonstrated by a preponderance of the evidence that claim 30 is
unpatentable under 35 U.S.C. § 103(a) as obvious over Terasawa, the
Immersion References, and Asai.
E. Carl Zeiss’s Motion to Exclude
The party moving to exclude evidence bears the burden of proof to
establish that it is entitled to the relief requested—namely, that the material
sought to be excluded is inadmissible under the Federal Rules of Evidence.
See 37 C.F.R. §§ 42.20(c), 42.62(a). For the reasons discussed below, Carl
Zeiss’s Motion to Exclude is denied.
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Carl Zeiss’s Motion to Exclude seeks to exclude (1) Exhibits 2036–
2039; (2) the portions of Mr. Juergens’ second cross-examination (Ex. 2040)
directed to those exhibits; (3) the Second Declaration of Dr. Sasian (Ex.
1054); and (4) portions of Patent Owner’s Motion for Observation
Regarding Second Cross Examination of Richard C. Juergens (Paper 30) as
lacking authentication (FRE 901), inadmissible hearsay (FRE 802), and
untimely. Paper 33.
We decline to assess the merits of Carl Zeiss’s Motion to Exclude. As
discussed above, even without excluding the identified evidence, we have
concluded that Carl Zeiss has demonstrated by a preponderance of the
evidence that the challenged claims are unpatentable. Accordingly, Carl
Zeiss’s Motion to Exclude is dismissed as moot.
F. Nikon’s Motion to Exclude
Nikon’s Conditional Motion to Exclude seeks to exclude Exhibits
1036 and 1038–1049 only if we grant Carl Zeiss’s Motion to Exclude
Nikon’s Exhibits 2036–2039. Paper 32, 1. As discussed above, Carl Zeiss’s
Motion to Exclude is dismissed as moot. Accordingly, we need not reach
Nikon’s Conditional Motion to Exclude.
III. CONCLUSION
Carl Zeiss has met its burden of proof by a preponderance of the
evidence in showing that claims 1–3, 8–12, 16–20, 23–26, and 29–33 of the
’575 patent are unpatentable based on the following grounds of
unpatentability:
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References Basis Claim[s] challenged
Terasawa and the
Immersion References
§ 103 1–3, 8–12, 16–20, 23–26, 29, and
31–33
Terasawa, the Immersion
References, and Asai
§ 103 30
IV. ORDER
Accordingly, it is
ORDERED that claims 1–3, 8–12, 16–20, 23–26, and 29–33 of the
’575 patent are held unpatentable;
FURTHER ORDERED that Carl Zeiss’s Motion to Exclude is denied;
FURTHER ORDERED that Nikon’s Motion to Exclude is dismissed;
and
FURTHER ORDERED that, because this is a Final Written Decision,
the parties to the proceeding seeking judicial review of the decision must
comply with the notice and service requirements of 37 C.F.R. § 90.2.
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For PETITIONER:

Marc M. Wefers, Esq.
Chris C. Bowley, Esq.
Lawrence Kolodney, Esq.
Kurt Glitzenstein
Fish & Richardson, P.C.
wefers@fr.com
bowley@fr.com
kolodney@fr.com
glitzenstein@fr.com

For PATENT OWNER:

John S. Kern, Esq.
Robert C. Mattson, Esq.
Oblon Spivak
CPdocketKern@oblon.com
CPdocketMattson@oblon.com